Step 2 - 地址生成与拆分

2026-04-14 00:56:38 +08:00
parent 7eab504f4a
commit 4ab93d7806
7 changed files with 266 additions and 10 deletions
@@ -0,0 +1,71 @@
+using System;
+
+namespace VMdemo.Core
+{
+    public static class AddressTranslatorUtils
+    {
+        public static AddressParts SplitVirtualAddress(ulong virtualAddress, int vaBits, int offsetBits)
+        {
+            if (vaBits <= 0 || vaBits > 64)
+            {
+                throw new ArgumentOutOfRangeException(nameof(vaBits), "vaBits 必须在 1 到 64 之间。");
+            }
+
+            if (offsetBits < 0 || offsetBits >= vaBits)
+            {
+                throw new ArgumentOutOfRangeException(nameof(offsetBits), "offsetBits 必须满足 0 <= offsetBits < vaBits。");
+            }
+
+            var vaMask = GetBitMask(vaBits);
+            if (vaBits < 64 && (virtualAddress & ~vaMask) != 0UL)
+            {
+                throw new ArgumentOutOfRangeException(nameof(virtualAddress), "virtualAddress 超出 vaBits 可表示范围。");
+            }
+
+            var vpnBits = vaBits - offsetBits;
+            GetPageTableBitLayout(vpnBits, out _, out var l2Bits);
+
+            var offset = virtualAddress & GetBitMask(offsetBits);
+            var vpn = virtualAddress >> offsetBits;
+            var l2Index = vpn & GetBitMask(l2Bits);
+            var l1Index = vpn >> l2Bits;
+
+            return new AddressParts(vpn, offset, l1Index, l2Index);
+        }
+
+        public static void GetPageTableBitLayout(int vpnBits, out int l1Bits, out int l2Bits)
+        {
+            if (vpnBits <= 0)
+            {
+                throw new ArgumentOutOfRangeException(nameof(vpnBits), "vpnBits 必须是正整数。");
+            }
+
+            l1Bits = (vpnBits + 1) / 2;
+            l2Bits = vpnBits / 2;
+        }
+
+        public static string FormatSplitResult(
+            ulong virtualAddress,
+            int vaBits,
+            int offsetBits,
+            AddressParts parts)
+        {
+            return $"VA={virtualAddress}, VPN={parts.Vpn}, Offset={parts.Offset}, L1={parts.L1Index}, L2={parts.L2Index}, vaBits={vaBits}, offsetBits={offsetBits}";
+        }
+
+        private static ulong GetBitMask(int bits)
+        {
+            if (bits <= 0)
+            {
+                return 0UL;
+            }
+
+            if (bits >= 64)
+            {
+                return ulong.MaxValue;
+            }
+
+            return (1UL << bits) - 1UL;
+        }
+    }
+}
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 1b0967dfe5b0eb64993e8c207604d159
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
@@ -0,0 +1,39 @@
+using System;
+
+namespace VMdemo.Simulation
+{
+    public class AddressGenerator
+    {
+        public const int DefaultSeed = 12345;
+
+        private readonly int _vaBits;
+        private readonly ulong _vaMask;
+        private readonly Random _random;
+        private readonly byte[] _buffer = new byte[8];
+
+        public AddressGenerator(int vaBits, int? seed = null)
+        {
+            if (vaBits != 32 && vaBits != 48 && vaBits != 64)
+            {
+                throw new ArgumentOutOfRangeException(nameof(vaBits), "vaBits 仅支持 32、48、64。");
+            }
+
+            _vaBits = vaBits;
+            _vaMask = vaBits == 64 ? ulong.MaxValue : (1UL << vaBits) - 1UL;
+            _random = new Random(seed ?? DefaultSeed);
+        }
+
+        public ulong MaxVirtualAddress => _vaMask;
+
+        public ulong NextVirtualAddress()
+        {
+            return NextRawUlong() & _vaMask;
+        }
+
+        private ulong NextRawUlong()
+        {
+            _random.NextBytes(_buffer);
+            return BitConverter.ToUInt64(_buffer, 0);
+        }
+    }
+}
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: a3e8a9161af494c43a623da1945f4373
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: